WHEN TURNING ON AUTOMATIC CLIMATE CONTROL THERE IS A HUM

2000 Ford Explorer • 10,400 miles

Hello!

I have a 2000 Ford Explorer fully loaded. It has the Climate control system, and when I turn on the heat using the AUTOMATIC button, instead of like, the FLOOR button, there is a fairly loud hum noise, and the electric system seems to bog down. If I hit the FLOOR button, it stops. This all while I have the temp set at 90 degrees. Seems to only occur when hitting the AUTOMATIC button.

the sound is kind of a low hum. Almost like a soft noise a car horn would make if the battery was about dead.

Noise description sounds like it is from the blend door actuators, when motors gets stuck.

Try this to see if you can find anything.
ENTERING SELF-DIAGNOSTICS

Ensure in-car temperature is between 40-90 F (4-32 C).
Turn ignition on.
Simultaneously depress OFF and FLOOR buttons, then press AUTOMATIC button within 2 seconds.
Display will show a pulse tracer going around center of the display window for up to 30 seconds while test is running.
Record all DTCs displayed.

One other question, while google searching others who had a simliar issue, they usually mention a ' clicking ' sound. Mine doesn't have a clicking sound, but a kind of hummmm If I just hit the FLOOR button, it doesn't do it, just when I hit the Automatic button. I think this 'blend door actuator' you are referring to is behind the glove box on the 2000 Ford Explorer, is that true? You have to remove the glove box insert to get to it? I am looking at the right part?